Serum concentration of cytokines. Serum concentration of cytokines in C57Bl/6 mice treated with topical oral gel containing propolis (GP) in comparison with the group treated only with the gel base (GS), or with saline (S). ELISA was used to determine the serum concentrations of IL-4 (A); IL-10 (B); IFN-γ (C) and TNF-α (D). The results represent mean ± standard deviation of 6 animals/group. (*) p < 0.05 in relation to the control and (#) p < 0.05 in relation to the other experimental group.